This invention is particularly intended to provide a beverage straw which will be attached to the exterior of the beverage container as the container is delivered to the consumer. A straw assembly attached to a beverage container should preferably have a length greater than a depth of the beverage container to give the user access to the entire contents of the container and prevent an inconvenience which would be experienced should the assembly fall into the container when in use. However, a straw assembly of a length to be conveniently used for this purpose will be substantially longer than the largest dimension of the associated beverage container and, therefore, it would be impossible to attach such straw assembly to the container and expect it to reach the user in useable condition. To overcome this problem, it is desired to provide a straw assembly which can be contracted when attached to the container and extended for actual use. Such an extensible straw assembly comprising an inner straw component telescopically inserted into an outer straw component is well known, but such straw assemblies of prior art construction have encountered various problems, as will be mentioned below because of their construction in which the telescoping ends of the inner and outer straw components are of two different interfitting diameters.
When such a straw assembly is extended and inserted into the container of beverage in actual use, the assembly can be properly handled so long as the inner straw component is pulled in a proper direction, i.e., with its forward end ahead, but the inner straw component will disengage from the outer straw component if the inner straw component is carelessly pulled out in the opposite direction. Further, such prior art straw assemblies have no means for reliably maintaining the assembly in the extended state, namely, no means by which the straw assembly is prevented from readily contracting again and there is a danger that the straw assembly might contract and fall into the container, if the user carelessly pushes the assembly against the bottom of the container.
In view of the problems as set forth above, an extensible straw assembly has already been developed and is well-known, having means to prevent the inner straw component from readily disengaging from the outer straw component and to prevent the assembly, once telescopically extended, from readily contracting again. To do this, the inner straw component has a diametrically flared or enlarged inner end or root portion while the outer straw, adjacent its forward end, has a diametrically reduced portion. Thus, the root of the inner straw engages the reduced forward end of the outer straw when the inner and outer straws are telescopically extended. Also, the outer straw component is further provided adjacent its forward end, e.g., at a boundary position between the blank portion and the diameter-reduced portion of the outer straw component with an inwardly projecting shoulder or stopper adapted to resist retraction of the inner straw into the outer straw.
This extensible straw assembly is very convenient in that the inner straw component is effectively prevented from accidentally disengaging from the outer straw component and the straw assembly, once fully extended, positively maintained in its extended condition without danger that the inner straw might be retracted into the outer straw due to careless handling. Additionally, this improved design provides the outer straw with a tapered portion the inner surface of which is adapted to be brought into surface-contact with the outer surface of the inner straw enlarged inner or root end to provide a seal preventing air leakage between the fully extended straws. However, it has been found to be very difficult to provide cylindrical or conical surfaces of the precise dimensions required to assure an exact surface-contact. Thus, to make straws of such design air seal effective, dimensional errors must be avoided as strictly as possible during production. Thus, quality control is very difficult and demanding, particularly in mass-production and such design involves a serious problem in implementing practice application. In addition, if it is attempted to improve dimensional precision in order to assure the desired airtightness, stickiness or resistance to telescopic movement would correspondingly in crease between the contacting surfaces of the inner surface of the outer straw's tapered portion and the outer surface of the inner straw's flared or root portion. Such stickiness can increase the resistance to telescopic adjustment to such an extent that some users such as children or women are unable to extend the straw assembly for use. Furthermore, if the diameter-reduced portion formed at the forward end of the outer straw is reshaped to present a relatively gentle angle of inclination, the inner straw would not be effectively locked by said diameter-reduced portion and may disengage the outer straw when the user tries to extend the straw assembly with the force necessary to overcome the high resistance due to stickiness.